1. Field of the Invention
The present invention relates generally to high speed weaving machines and more particularly to an improved heald or heddle frame for a high speed weaving machine.
2. Description of the Prior Art
A heddle frame used in a weaving machine conventionally is composed of a pair of side stays 2, 2 and a pair of cross beams 1, 1 as shown in FIGS. 1A and 1B wherein the bending state in a shedding motion of an ordinary heddle frame is illustrated. The side stay portion of the heddle frame is free to slide in a guiding groove formed in a guiding apparatus to make a shedding motion. With respect to a high speed weaving machine, which makes a shedding motion with rotation of 300-600 rpm, a joining device is very complex and heavy in weight, so as to strengthen the joint between a side stay and a cross beam, and, as the shedding motion of a heddle frame is very high in speed the inertia of the heddle frame, owing to the weight thereof, is very large. Accordingly, breaking of the heddle frame thus occurs readily to reduce the life thereof. Other defects of the conventional heddle are that they wear quickly and they generate substantial noise.
To overcome such defects, a hollow cross beam made of aluminum has been used to make a heddle frame which is light in weight and to make the inertia of the weight of the heddle frame small. However, the bending of the pair of cross beams 1, 1 during a shedding motion cannot be prevented. That is to say, according to shedding motion, the phenomenon that a pair of cross beams 1, 1 bend as shown in FIG. 1(A) and FIG. 1(B) arises. During this phenomenon, since the strength of the pair of side stays 2, 2 is greater than that of the pair of cross beams 1, 1, the side stays 2, 2 cannot bend, respectively, as shown by the dotted lines in FIG. 1(A) and FIG. 1(B). Therefore, the largest moment is applied to the joining portion of the side stays and the cross-beams and the joining portion is thus cut or broken. When a bolt is used for joining the side stay and the cross beam, such problems as cutting of the bolt or loosening of the bolt and a respective nut occur. Most of the breaks of ordinary heddle frames are due to cutting of the joint material or cutting of the joining portion.